The 'knee' pattern in spirometry flow-volume curves in children: Does it relate to tracheomalacia?
Respir Med
; 204: 107029, 2022.
Article
in En
| MEDLINE
| ID: mdl-36335911
ABSTRACT
BACKGROUND:
There is little data on patterns of spirometry curves in children with tracheomalacia but convex inflection on flow-volume curves (identified as the 'knee') is thought to represent tracheomalacia.OBJECTIVES:
To determine (a) the prevalence of tracheomalacia in children with the 'knee' pattern on spirometry, and (b) whether spirometry parameters and visual characteristics of the 'knee' can identify presence/absence or severity of tracheomalacia. PATIENTS/METHODS:
We reviewed the spirometry undertaken at Queensland Children's Hospital between 2016 and 2019 and retrieved spirometry with the 'knee' pattern in the flow-volume curves. Flexible bronchoscopy videos of these children were reviewed for tracheomalacia diagnosis and severity in a blinded manner. We also evaluated several 'knee' characteristics (onset of inflection, angle of inflection, a scoop before plateau, plateau progression), spirometry parameters and tracheomalacia severity.RESULTS:
Of the 78 children with the 'knee', 51 (65.4%) had tracheomalacia. Spirometry values were significantly lower in those with tracheomalacia, compared to those without (predicted FEV1 = 86.1% vs 99.9%, FVC = 95.1% vs 104%, FEF25-75% = 68.6% vs 89.6%, all p < 0.02). A scoop before plateau was significantly associated with tracheomalacia (66.7% vs 40.7%, p = 0.03). There was no significant difference in spirometry parameters or the 'knee' characteristics between children with mild versus moderate-to-severe tracheomalacia.CONCLUSION:
Most but not all children with the 'knee' pattern have flexible bronchoscopy-defined tracheomalacia. Those with tracheomalacia had lower spirometry values and the presence of a scoop before plateau was the most characteristic feature. A prospective longitudinal study is required to determine the diagnostic value of spirometry flow-volume curve characteristics in children.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Tracheomalacia
Type of study:
Diagnostic_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Child
/
Humans
Language:
En
Journal:
Respir Med
Year:
2022
Document type:
Article